In the field of drafting, it is often necessary to have a translucent flat surface which is illuminated from behind. Such a surface would be used when it is desired to trace drawings, or for other similar purposes. Typically, a drawing table is utilized which has a translucent surface and lights mounted below that translucent surface, which lights are usually fluorescent lights. The translucent surface and the lights are often fixed in position. Such a fixed arrangement is inconvenient since in many cases a draftsman may wish to alter the angle of the translucent surface for comfort and convenience. In many prior art devices which allow the angle of the translucent surface to be adjusted with respect to horizontal, the lights though are fixed in a position for the usually desired intensity of light on the translucent surface, and even distribution of it, only when the translucent surface is at a particular angle. When such angle is altered, as a result of the fixed position of the lights, the intensity of light on the translucent surface may be undesirably decreased or increased, and the even distribution of the light altered.
Devices have been suggested in the past which have attempted to overcome such problems. One such device is disclosed in U.S. Pat. No. 2,328,471 to Leffel. The device as disclosed in that patent is provided with a top which can pivot to varying angles with respect to a base. An elongated light, such as a fluorescent light tube, is disposed in a position spaced underneath a transparent surface (which term is used throughout this application to include translucent surfaces) so as to cause light from the tube to pass through the transparent surface. A reflector of rigid material is then provided which is of a curved shape and disposed beneath the light tube so as to reflect light relatively evenly from it and through the transparent surface such that the transparent surface is relatively evenly illuminated. A difficulty with the foregoing device is that the light tube and rigid reflector must extend at positions considerably far removed from the underside of the transparent surface, if relatively even illumination of the transparent surface is to be obtained. Because of the foregoing rigid construction, when the top is pivoted to a closed position adjacent the base, the device is still bulky in terms of it being fairly thick so that the light tube and reflector are contained within the device.
It is desirable then to have a drawing table with a top which can pivot to an open position with respect to a base, and which has a construction to provide relatively even illumination of a transparent opening in the top, while allowing the top to move to a closed position adjacent the base in which closed position the drawing table is relatively compact particularly in terms of thickness, for convenient transportation and storage.